Tracheostomy is a common surgical procedure involving the surgical creation of an opening into the trachea through the neck for insertion of a tube to facilitate the passage of air to the lungs or the evacuation of secretions. Tracheostomy is usually done to provide an adequate airway for prolonged ventilatory support, to bypass obstruction of the upper part of the respiratory tract and for pulmonary toilet.
Tracheostomy tubes are usually made of plastic such as polyethylene. All are curved to accommodate the anatomy of the trachea. The plastic tracheostomy tubes presently in use have an inflatable cuff attached. The inflatable cuff is built on the outer surface of the cannula. The purpose of the cuff is to hold the tube in place and prevent the flow of air around the outside of the cannula. This allows for more effective ventilation of the patient and prevents the aspiration of liquids and foods into the trachea. Tracheostomy tubes may consist of single or double cannulas. Double cannula tubes include an outer cannula to maintain the patency of the airway and an inner cannula that fits snugly inside the outer cannula and can be removed for cleaning and removal of accumulated secretions without disturbing the operative site.
An accessory to tracheostomy tubes is the obturator or pilot, which is an olive tipped curved rod that is placed within the tracheostomy tube so that its atraumatic tip extends just forward of the distal end of the tracheostomy tube. The tip of the obturator is used to guide the tracheostomy tube into the trachea and prevent damage to the tracheal walls while the tube is being inserted. Once the tracheostomy tube has been inserted, the obturator has served its purpose and it is removed from the center of the tracheostomy tube.
A significant problem with present tracheostomy tubes is the difficulty which attends the change of the tracheostomy tube or replacement of a dislodged tube. Substantial problems may occur, for example, in replacing tracheostomy tubes in obese patients, in the patient with a recent tracheostomy, and in patients with scarring in the area. The airway is essential. If the tube is dislodged, the soft tissue surrounding the tracheostomy wound obstructs the airflow, preventing the patient from breathing. During the period between removal of the old tube and insertion of the new tube, access to the tracheal area can constrict or may have already become so edematous that insertion of the new tube may be difficult or impossible because of inadequate anatomic definition. Thus, the method of reintubation may expose the patient to risks of bleeding, trauma, airway perforation, or loss of airway which may add potential complications to the procedure or lead to death.
Another significant error which can occur, is the placement of the tube in the pretracheal space in which the inflated cuff blocks the airway and the mediastinum is insufflated with air from a respirator. Such an error compromises venous return while failing to maintain adequate oxygen exchange. Continuing forceful attempts to replace the tube compresses the trachea and blocks any air exchange. In obese patients, shorter tracheostomy tubes may not be advanced far enough into the trachea and may dislodge to the pretracheal space when the patient's head is repositioned.
These inherent risks would potentially expose the patient to inadequate ventilation, oxygenation and/or airway control during this period of loss of function and the presence of the tracheostomy tube. In a situation where a patient requires a tracheostomy tube to assist in a patient's life support system, any delay may present potentially serious complications and/or death. In addition, tracheal tube replacement is considered a procedure carrying a degree of associated risk whose completion requires highly trained practitioners.
Thus, efficient ways of replacing or changing a tracheostomy tube have been sought which avoid problems of tracheal ulcer and damage and permits insertion directly into the trachea.
In McQuarrie, "Safe Replacement of Tracheostomy Tubes", Surgery, Gynecology and Obstetrics, 140, 769.770 (1975), several methods useful in the routine management of tracheostomies are disclosed among which is the use of a catheter as a guide tube. This reference discloses that when changing the tube in a new tracheostomy, a suction catheter can be inserted through the tube to be removed. The tube is then removed over the catheter, leaving a good length of the catheter in the trachea. The new tracheostomy tube may then be slid into proper position over the catheter. U.S. Pat. No. 4,960,122 to Mizus also discloses use of such a guide tube. These methods, however, are not without drawbacks as the conventional obturator cannot be used and the opening into the trachea may be scarred, torn or distorted, preventing the new tracheostomy tube from being inserted into the trachea over the guide.